1. Field of the Invention
This invention relates to a preparation for topical application containing menthol and/or camphor and to a process for producing the same.
2. Description of the Prior Art
Anti-inflammatory, analgesic and anti-pruritic preparations for topical uses containing menthol and/or camphor as active ingredient(s) have heretofore been used in the form of an ointment, liniment or tincture for percutaneous applications. However, ointments feel sticky and unpleasant when applied to the skin, possibly soiling clothes, while the active ingredient applied is not always fully absorbable through the skin. Particularly at high temperatures, ointments are liable to become unstable. With liniments and tinctures, the active ingredient can be percutaneously absorbed more effectively than in ointments, but the volatile active ingredient, i.e. menthol or camphor, is volatilized by the body temperature and thus fails to give a sustained medicinal efficacy.
Methyl cellulose, carboxymethyl cellulose, etc. are known to be polymer compounds which, when applied to the skin, form a membrane. However, for use in an aqueous alcohol solution containing menthol and/or camphor, a large quantity of such a polymer compound must be incorporated into the solution to impart the desired viscosity to the resulting preparation. Additionally, when applied to the skin, the preparation requires a long time for the formation of a membrane, feels sticky and is therefore unsuitable for use.